<template>
  <el-row>
    <canvas
      id="verification_code_image"
      ref="verification_code_image"
      :width="width"
      :height="height"
      @click="draw"
    ></canvas>
  </el-row>
</template>

<script>
export default {
  props: {
    width: {
      type: Number,
      default: 100
    },
    height: {
      type: Number,
      default: 50
    }
  },
  data() {
    return { code: '', uuid: '' }
  },
  mounted() {
    this.draw()
  },
  methods: {
    async draw() {
      const {
        status,
        data,
        data: {
          data: { code, uuid }
        }
      } = await this.$axios.get('/public/VCode')
      if (status === 200 && data.code === 1) {
        this.code = code
        this.uuid = uuid
        this.$emit('setUuid', uuid)
      }
      const showNum = []
      const canvas = this.$refs.verification_code_image
      const canvasWidth = canvas.width
      const canvasHeight = canvas.height
      const context = canvas.getContext('2d') // 获取到canvas画图的环境，演员表演的舞台
      context.fillStyle = '#ffffff'
      context.beginPath()
      context.fillRect(0, 0, canvas.width, canvas.height)
      context.closePath()
      // const sCode =
      //   'a,b,c,d,e,f,g,h,i,j,k,m,n,p,q,r,s,t,u,v,w,x,y,z,A,B,C,E,F,G,H,J,K,L,M,N,P,Q,R,S,T,W,X,Y,Z,1,2,3,4,5,6,7,8,9,0'
      // const aCode = sCode.split(',')
      // const aLength = aCode.length // 获取到数组的长度

      for (let i = 0, len = this.code.length; i < len; i++) {
        // 这里的for循环可以控制验证码位数（如果想显示6位数，4改成6即可）
        // const j = Math.floor(Math.random() * aLength) // 获取到随机的索引值
        // var deg = Math.random() * 30 * Math.PI / 180;//产生0~30之间的随机弧度
        const deg = Math.random() - 0.5 // 产生一个随机弧度
        // const txt = aCode[j] // 得到随机的一个内容
        const txt = this.code[i]
        showNum[i] = txt.toLowerCase()
        const x = 10 + i * 20 // 文字在canvas上的x坐标
        const y = 20 + Math.random() * 8 // 文字在canvas上的y坐标
        context.font = 'bold 23px 微软雅黑'

        context.translate(x, y)
        context.rotate(deg)

        context.fillStyle = this.randomColor()
        context.fillText(txt, 0, 0)

        context.rotate(-deg)
        context.translate(-x, -y)
      }
      for (let i = 0; i <= 5; i++) {
        // 验证码上显示线条
        context.strokeStyle = this.randomColor()
        context.beginPath()
        context.moveTo(
          Math.random() * canvasWidth,
          Math.random() * canvasHeight
        )
        context.lineTo(
          Math.random() * canvasWidth,
          Math.random() * canvasHeight
        )
        context.stroke()
      }
      for (let i = 0; i <= 30; i++) {
        // 验证码上显示小点
        context.strokeStyle = this.randomColor()
        context.beginPath()
        const x = Math.random() * canvasWidth
        const y = Math.random() * canvasHeight
        context.moveTo(x, y)
        context.lineTo(x + 1, y + 1)
        context.stroke()
      }
    },
    randomColor() {
      const r = Math.floor(Math.random() * 256)
      const g = Math.floor(Math.random() * 256)
      const b = Math.floor(Math.random() * 256)
      return 'rgb(' + r + ',' + g + ',' + b + ')'
    }
  }
}
</script>

<style lang="scss" scoped>
#verification_code_image {
  vertical-align: middle;
  box-sizing: border-box;
  border: 1px solid #ddd;
  cursor: pointer;
}
</style>
